Many thousands of individuals work in locations and positions which are elevated above the ground or above some other safe platform located above the ground. Likewise, many individuals, such as deer hunters who hunt from treestands, rock climbers, and others engage in a variety of recreational activities in elevated positions above the ground. In such elevated positions, the risk of injury or death from an accidental fall is a real and ever-present concern. Numerous designs for various types of fall-arrest systems have been developed over the years to protect workers and others from sustaining impact injuries or death in the event of accidental falls from elevated locations. One of the most common and widely-used fall-arrest systems is the so-called “full-body safety harness”, which typically comprises an assemblage of webbing components configured to be worn by the user, with leg straps and a waist belt for support of the torso. A tether attached to the harness is generally connected to an anchor point above the user's head. In the event of a fall, the harness is designed to arrest the person's fall, and to provide support until rescue from the suspended condition can be achieved.
In recent years, experience and research have taught that a person who remains suspended in a safety harness after an arrested fall runs an extremely high risk of experiencing suspension trauma. Suspension trauma refers to the sequence of events likely to be experienced by a suspended fall victim after an arrested fall, as a result of the interruption of blood flow to and from the lower extremities. This circulatory interruption is commonly caused by the impingement of the leg straps on the large arteries and veins of the upper leg and groin region. The condition arises soon after becoming suspended in a harness after a fall, and begins with pain in the groin region, then progresses to loss of feeling in the feet or toes of the victim, then to loss of feeling in the legs, followed by unconsciousness. Death due to circulatory insufficiency is the ultimate result, unless the victim can be rescued immediately after the fall. The longer the fall victim remains suspended, the greater the danger. Indeed, the danger of suspension trauma has only become widely known within the past several years. The condition is now being addressed as a serious risk, through revised ANSI standards for fall-protection systems and equipment. Likewise, it is a subject of serious concern to the Consumer Products Safety Commission, due primarily to the likelihood of the condition affecting hunters who fall from treestands, even thought their harnesses may have prevented them from impact injury or death.
If there is no outside assistance available to provide for the rescue of a suspended fall victim, then the preferred approach to avoiding suspension trauma is through some means of rapid self-rescue. Self-rescue involves enabling the fall victim to return to a place of safety quickly, without assistance. Immediate self-rescue after a fall is the key to improved survival chances. Self-rescue is particularly important in the case of hunters and workers who are working alone without nearby and available sources of assistance. The current invention is designed to provide self-rescue by providing a safe and gentle descent back to the ground or other safe platform just as soon as the fall has been arrested.
Fall-protection devices and emergency descent systems related to fall protection are well-known in the art, and date back for many decades. Such devices generally exhibit one or more limiting characteristics which render them inappropriate for use as a personal, automatic emergency descent system. Such limiting characteristics include (1) dependence on operator activation, control, and technique, usually requiring elaborate training (2) a requirement for the user to be agile and/or athletic in order to safely use such systems, (3) either overly complex or overly simplistic designs which are not sufficiently user-friendly to ensure safe operation.
Descender systems designed for emergency descent from a stationary anchor point, usually in industrial environments, are also well-known, as illustrated by United States Published Patent Application No. 2002/0179372, which discloses an exceedingly complex, heavy, and expensive device. Its complexity would predictably lead to high cost and possibly compromised reliability. Further, the device is far too large and heavy to be used by great numbers of people in diverse circumstances, or in applications where the system needs to be easily transportable, perhaps to remote locations. This system and others do not meet the parameters of a “personal” self-rescue device which is highly affordable, compact, light-weight, user-friendly, simple, and reliable. Devices which do not meet these requirements would be very difficult to market, due to high cost and low user acceptance levels, except in certain very high-end industrial environments. In short, such systems have not been welcomed and acquired by large numbers of the users who actually do need to be using such protective gear.
A number of other designs have been proposed over the years to address the area of self-rescue, but the majority of these, especially those which involve mountaineering or climbing-type devices or systems, demand training skill, athleticism, and precise techniques on the part of the user. In many cases, because of their common use of heavy climbing ropes, they tend to be complicated, cumbersome, bulky, and expensive systems, well-suited for only a minority of the people who might need them.
No other system known provides the capability and convenience, as the present invention does, for the descender/self-rescue device to be worn or used continuously and comfortably by the wearer, or the ability to automatically lower a fall victim who may be unconscious or disabled. A personal descender which involved a stored coil of webbing and attempted to use a rappelling-rack-based braking system, was introduced in approximately 2003 (The Fall Guy Descender, as mentioned in United States Published Patent Application No. 2006/0113147), but the device was removed from the market due to various difficulties. Other rappelling-type devices with bags for storage of the rappelling line are known, but again, virtually all of these require the user to employ a certain degree of skill and athleticism in initiating the descent.
Personal descender designs are not unknown in the art. Few of these have found commercial success outside the industrial and commercial arenas. One type of a personal descender employs a stored line used in conjunction with a separate device which employs a helical groove around a body through which the line is pulled upon initiation of a descent, which arrangement provides a frictional resistance to payout of the line. However, the this type of a system involves many highly-precise, complex, costly, interconnecting, and close-fitting parts, and does not integrate the stored line with the braking mechanism into one, compact, simple, lightweight and affordable module, as the present invention does.
While differing types of emergency escape and descent systems are known in the art, such descenders are most often designed to be attached to an anchor point, to which a user would connect some type of harness tether, for the purpose of descending from an elevated location in the event of an emergency. Most are not designed to anticipate or to accommodate the needs of a worker or person involved in activities and moving around at various heights who might sustain an accidental fall at any time or in any place where he or she might be working. Further, such industrial descenders are (a) not designed to be worn in conjunction with or as part of a safety harness, (b) are typically too large and heavy (15 to 25 lbs., for example) to be practical for workers to wear or carry around, and (c) are exceedingly expensive, costing $1,200 to as much as $2,500 each, and (d) are typically very complex, involving many expensive precision moving parts. By contrast, the present invention in a preferred version weighs approximately 1.5 lbs, is very compact (comparable to a compact-disc player in size), utilizes no moving parts other than the descent webbing, and is very economical.